Generic Alprostadil comes in two different dosages: 10mcg and 20mcg vials. These vials are mixed with a solution before the prescribed dose is injected. You’ll typically start on 2.5mcg of Alprostadil and work your way up until you find a dose that works for you.
Finding the right dosage of Alrpostadil can take time, though. The standard dosage tends to be between 5mcg and 20mcg, which is usually effective for the men using it.
Your doctor will slowly increase the dosage to find the right one for you, minimising risks and maximising effectiveness, a process called titration. If you find the medication doesn’t provide you with the results you need without unwanted side effects, a different erectile dysfunction treatment might be suggested.
Alprostadil used to be available under the brand Caverject, but this was discontinued in 2025. Caverject came in 10mcg, 20mcg, and 40mcg vials. A version of Caverject with an easy-to-use syringe that helped mix the medicine for you was also available, called Caverject Impulse Dual Chamber. This only came in 10mcg or 20mcg doses.
While generic Alprostadil isn’t currently available in the 40 mcg dose, it contains the same active ingredient and works in the same way as Caverject – so it’s a good option if you’re looking for Caverject alternatives.
Are Viridal dosages the same as Alprostadil?
Viridal Duo comes in the same doses as Alprostadil (10mcg, 20mcg), as well as a 40mcg dose. It’s essentially the same product as Alprostadil in regards to its active ingredient, it’s just available at a higher dosage. Whilst both products are injected, the injection devices aren’t the same, so the instructions will differ slightly. Viridal Duo comes in an Easy-Duo syringe, which helps mix the active ingredient with a solution for you. If you’re using generic Alprostadil, you’ll need to mix it with this solution in a vial yourself.
If you’re swapping between Alprostadil or Caverject and Viridal, be sure to tell your prescribing clinician so they can make sure you’re comfortable with the new instructions.
Caverject Dual Chamber, Alprostadil Vials & Viridal Duo 10mcg
The lowest dosage product available for alprostadil injections is 10mcg. Alprostadil 10mcg vials, Caverject Dual Chamber and Caverject 10mcg vials are essentially the same product – but the Dual Chamber device was unique to Caverject, whereas the vials are mixed manually before being administered through a needle. You can set the dosage on the device or, when using the vials, it can be measured on the syringe.
The Viridal 10 starter pack uses the EasyDuo device, its instructions differ slightly from the Caverject Dual Chamber or the vials.
At the start of your treatment, it’s likely that your doctor will recommend a dosage of 2.5mcg to 5mcg, whichever the product. The 10mcg dosage is the lowest of the standard products but it’s usually effective enough for most that use it.
If you don’t achieve the results you want from this dosage, and you haven’t experienced any unpleasant side effects, your prescribing clinician might suggest increasing the dosage.
Caverject Dual Chamber, Alprostadil Vials & Viridal Duo 20mcg
Alprostadil 20mcg injections are at the higher end of the standard dosages. As you might expect, they’re more reliable but also present a higher risk of side effects.
This also goes for the Viridal Duo 20mcg continuation pack, although it’s likely you’ll only be prescribed this if you’ve tolerated treatment well. If this dosage is still found to be lacking, it can still be increased to 40mcg.
Caverject Vials & Viridal Duo 40mcg
The 40mcg dose was the highest dosage of Caverject and is the highest dose Viridal Duo. There is no generic Alprostadil 40mcg dosage right now.
It’s unlikely your doctor will prescribe this dosage as a starting point, unless you have previous experience with the medication and it was found that the dosage didn’t cause you any side effects. More often than not, you’ll build up to 40mcg of alprostadil after the lower strength products have been found to be ineffective.
